Conventionally, it has been well known that in an image forming apparatus such as a printer, copier and the like, a toner container for storing toner such as a toner bottle, a toner cartridge and the like is set up on the main body of the same apparatus and toner is supplied from the container to a developing portion. In this kind of the toner container, a toner discharging port is closed with a cap or seal so that upon replacement of the container, user has to remove that cap or seal. However, this work causes scattering of toner or contamination by toner, therefore user does not like to do such a work. Thus, since before, various devices and proposal have been made for user to carry out the replacement work of the toner container comfortably.
For example, a toner container provided with a self-closing valve at a toner discharging port thereof has been already proposed. Such a toner container can be set up in the apparatus without removing the cap or seal. FIG. 23 shows an example of the toner container provided with the self-closing valve, which the same applicant as this application has already proposed.
Referring to FIG. 23, a mouth ring 23, in which the toner discharging port is formed of the toner container 20, is provided with a seal valve 60 made of non air-permeable sponge as the self-closing valve. Slits 65, which intersect each other substantially in the center, are formed in the sealing valve 60. On the other hand, a nozzle 40, which serves as an insertion member, is erected in a setting portion 50 in the main body of the apparatus in which the toner container 20 is to be set up. When the toner container 20 is set in the setting portion from above, the nozzle 40 is inserted through the slits 65 in the sealing valve 60. At this time, the slits 65 in the sealing valve 60 are outstretched so as to make firm contact with an external periphery of the nozzle 40 without any gap. If the toner container 20 is pulled out of the setting portion, the outstretched slits 65 return to their original states by elasticity of the sponge seal 22.
However, the aforementioned toner container 20 has such a problem that toner leaks from the slits 65 in the sealing valve 22, so that the setting portion 50 is contaminated. Major reasons for such a problem are as follows.
The nozzle 40 is not located in the center of the sealing valve 60. Moreover, when the nozzle 40 is inserted into the sealing valve 60 or removed therefrom, gap is generated between the slits 65 and the nozzle 40. Moreover, the sealing valve 60 creeps thereby lowering sealing effect. In addition, when the nozzle 40 is pulled out, toner deposited on the nozzle 40 upon setting spills out.